Yemeni security forces have foiled a plot by al-Qaeda to take over oil and gas export facilities and a provincial capital in the eastern part of the country, a government official said today.

Rajeh Badi, press advisor to Yemeni Prime Minister Mohammed Salem Basindwa, said the plan involved dozens of al-Qaeda militants dressed in Yemeni army uniforms storming the facilities on the night of the 27th of Muslim month of Ramadan, which was on Sunday.

“The plot aimed to seize the al-Dabbah oil export terminal in Hadramout (province) and the Belhaf gas export facility, as well as the city of Mukalla,” Mr Badi told Reuters, referring to the Hadramout provincial capital. He said the plot was prevented by deploying extra troops around the targeted facilities and banning anyone from entering.

The strikes in Shabwa province came a day after the US and Britain evacuated embassy staff due to a threatened attack in the country, and militants shot down a helicopter.

Security officials believe the terror network is seeking retaliation for a US-backed military offensive that has dealt serious setbacks to its most active branch, including the death earlier this year of its second-in-command.

The Yemeni army, meanwhile, surrounded foreign installations, government offices and the airport with tanks and troops in the nation’s capital, Sanaa, as well as the strategic Bab al-Mandeb straits at the entrance to the Red Sea in the southern Arabian Peninsula.

It drew parallels with security measures following the 2000 bombing of the USS Cole in Aden harbour that killed 17 American sailors.

Authorities also set up checkpoints across Sanaa, searching cars and individuals, especially after night fell. Government officials, along with military and security commanders, were told to stay vigilant and limit their movements.

Although the immediate threat seemed to be focused on Yemen, the US has temporarily shut down 19 diplomatic posts in the Middle East and Africa.

A US intelligence official and a Middle East diplomat said the closures were triggered by the interception of a secret message between al Qaeda chief Ayman al-Zawahri and Nasser al-Wahishi, the leader of the Yemen-based al Qaeda in the Arabian Peninsula, about plans for a major terror attack.

Mr Zawahri also made a public statement on July 30 that urged Muslims to kill Americans “in every spot on Earth”.

Yemeni investigators looking into the threat said they believe the motive of the attack was retaliation for the killing of Saudi-born Saeed al-Shihri, who was released from the US prison in Guantanamo Bay after nearly six years and later became the second-ranked al Qaeda leader in Yemen.

He was critically wounded in a November drone strike and later died of his wounds.

The terror network has suffered a series of setbacks after the military launched an offensive in June with the help of US forces that has succeeded in uprooting it from strongholds in the south.

The group had taken advantage of the instability after the Arab Spring wave of revolutions that led to the resignation of Yemen’s longtime leader, Ali Abdullah Saleh.

Yemen’s current president, Abdo Rabby Mansour Hadi, met President Barack Obama at the White House last week, where both leaders cited strong counter-terrorism co-operation.

The US Air Force transported State Department personnel out of Sanaa early yesterday.

The department said in a travel warning that it had ordered the departure of non-emergency US government personnel “due to the continued potential for terrorist attacks,” adding that US citizens should leave immediately because of an “extremely high” security threat level.

The British Foreign Office also evacuated all staff from its embassy due to increased security concerns. And the Dutch Foreign Ministry has issued a call for about 40 of its citizens to leave Yemen.

Yemen’s government criticised the evacuations, saying the diplomatic withdrawal “serves the interests of the extremists and undermines the exceptional co-operation” between Yemen and the international community in fighting terrorism.

It insisted that its government has taken all precautions to ensure the security of foreign missions in Sanaa.